Ethanol can be produced from grain-based feedstocks (e.g. corn, sorghum/milo, barley, wheat, soybeans, etc.), from sugar (e.g. from sugar cane, sugar beets, etc.), and from biomass (e.g. from cellulosic feedstocks such as switchgrass, corn cobs and stover, wood or other plant material).
Biomass comprises plant matter that can be suitable for direct use as a fuel/energy source or as a feedstock for processing into another bioproduct (e.g., a biofuel such as cellulosic ethanol) produced at a biorefinery (such as an ethanol plant). Biomass may comprise, for example, corn cobs and stover (e.g., stalks and leaves) made available during or after harvesting of the corn kernels, fiber from the corn kernel, switchgrass, farm or agricultural residue, wood chips or other wood waste, and other plant matter. In order to be used or processed, biomass will be harvested and collected from the field and transported to the location where it is to be used or processed.
In a biorefinery configured to produce ethanol from biomass such as cellulosic feedstocks, ethanol is produced from lignocellulosic material (e.g. cellulose and/or hemi-cellulose). The biomass is prepared so that sugars in the cellulosic material (such as glucose from the cellulose and xylose from the hemi-cellulose) can be accessed and fermented into a fermentation product that comprises ethanol (among other things). The fermentation product is then sent to the distillation system, where the ethanol is recovered by distillation and dehydration. Other bioproducts such as lignin and organic acids may also be recovered as co-products. Lignin recovered from the cellulosic ethanol production process can be used as an energy source or as a feedstock for other chemicals or products.
Lignin is a complex mixture of aromatic compounds found in lignocellulosic biomass, such as wood, corn cobs and corn stover, switchgrass and other plant materials. Due to its high energy content, comparable to that of coal at about 8000 to 11000 BTU per pound of lignin, lignin may be used to produce renewable energy by combustion. Lignin may also be used as an additive in polymers or as a feedstock for other chemicals and products, such as adhesives, binders and carbon fibers.
It would be advantageous to provide for a pellet comprising lignin. It would also be advantageous to provide for a system for producing pellets comprising lignin. It would further be advantageous to provide for a system for producing lignin pellets from pre-treated and fermented biomass. It would further be advantageous to provide for a system that provides one or more features to facilitate improvement in the efficiency and yield of cellulosic ethanol from biomass.